Michael John Douglas was born September 5, 1951. When he became an actor, he had to change his stage name, as Michael Douglas was already in the Screen Actors Guild (there cannot be two actors with the same screen name in the Guild). I don't know if he considered it, but he couldn't shorten his name to Mike Douglas, because of the TV talk show host Mike Douglas. Of course, Mike Douglas the TV star was born Michael Dowd. On a whim, Michael John Douglas saw a picture of actress Diane Keaton and chose the name Michael Keaton.
Diane Keaton was born Diane Hall. Diane Hall changed her last name to her mother's maiden name Keaton as a result of a Diane Hall already being in the Screen Actors Guild. Diane Hall has one screen credit to her name- Jethro's Daughter in Cecil B. Demille's The Ten Commandments.
What does this teach us? Issur Danielovitch should have renamed himself Kirk Daniels!